Magnetite increases the density of most mixtures in which it is present. This property allows magnetite to be used in the manufacture of heavy concrete, water filtration, coal mining, landscaping and production of certain iron-based chemicals.
When magnetite is added to a concrete mix, it produces heavy concrete, which is twice as dense as standard concrete. Heavy concrete is widely used in buildings that require protection from radiation, such as nuclear power plants, X-ray facilities and uranium mining sites. Heavy concrete retains heat more efficiently than standard concrete and can be used in building houses to retain solar heat.
Magnetite can also be used in water filtration systems. A water filtration system with magnetite has a more aggressive backwash in the cleaning phase, as well as the ability to recover the magnetite by using a magnet.
It is also used in coal mining operations as a slurry with water to remove the heavier impurities by allowing the less dense coal to float to the surface. The magnetite can be reused in this process 90 percent of the time.
Magnetite is also used as a source of iron to manufacture iron-based chemicals and fertilizers. Ferric chloride and ferric sulphate are manufactured with magnetite as one of the starting materials. These chemicals are effective in clarifying raw water in water purification plants. The dark, glossy nature of magnetite ore has led to its use in landscaping as accent rocks.